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Acute acetaminophen ingestion does not alter core temperature or sweating during exercise in hot–humid conditions
Author(s) -
Coombs G. B.,
Cramer M. N.,
Ravanelli N. M.,
Morris N. B.,
Jay O.
Publication year - 2015
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.12336
Subject(s) - ingestion , core temperature , acetaminophen , medicine , core (optical fiber) , thermoregulation , anesthesia , materials science , composite material
Acute acetaminophen ( ACT ) ingestion has been reported to reduce thermal strain during cycling in the heat. In this study, nine active participants ingested 20 mg of ACT per kg of total body mass ( ACT ) or a placebo ( PLA ), 60 min prior to cycling at a fixed rate of metabolic heat production ( ACT : 8.3 ± 0.3 W /kg; PLA : 8.5 ± 0.5 W /kg), which was equivalent to 55 ± 6% VO 2max , for 60 min at 34.5 ± 0.1 ° C , 52 ± 1% relative humidity. Resting rectal temperature ( T re ; ACT : 36.70 ± 0.17 ° C ; PLA : 36.80 ± 0.16 ° C , P = 0.24), esophageal temperature ( T es ; ACT : 36.54 ± 0.22 ° C ; PLA : 36.61 ± 0.17 ° C , P = 0.50) and mean skin temperature ( T sk ; ACT : 34.00 ± 0.14 ° C ; PLA : 33.96 ± 0.20 ° C , P = 0.70) were all similar among conditions. At end‐exercise, no differences in Δ T re ( ACT : 1.12 ± 0.15 ° C ; PLA : 1.11 ± 0.21 ° C , P = 0.92), Δ T es ( ACT : 0.90 ± 0.28 ° C ; PLA : 0.88 ± 0.23 ° C , P = 0.84), Δ T sk ( ACT : 0.80 ± 0.39 ° C ; PLA : 0.70 ± 0.46 ° C , P = 0.63), mean local sweat rate ( ACT : 1.02 ± 0.15 mg/cm 2 /min; PLA : 1.02 ± 0.13 mg/cm 2 /min, P = 0.98) and whole‐body sweat loss ( ACT : 663 ± 83 g; PLA : 663 ± 77 g, P = 0.995) were evident. Furthermore, ratings of perceived exertion and thermal sensation and thermal comfort were not different between ACT and PLA conditions. In conclusion, ACT ingested 60 min prior to moderate intensity exercise in hot–humid conditions does not alter physiologic thermoregulatory control nor perceived strain.